Domestic refrigerator sizing: Select the typical capacity range (in tonnes of refrigeration, TR) for a household refrigerator.
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A0.1 to 0.3 TR
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B1 to 3 TR
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C3 to 5 TR
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D5 to 7 TR
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E0.5 to 1.0 TR
Answer
Correct Answer: 0.1 to 0.3 TR
Explanation
Introduction / Context:Household refrigerators are small refrigeration units compared to comfort-cooling or industrial systems. Knowing the typical capacity range helps students relate theory to real appliances.
Given Data / Assumptions:
- Capacity is quoted in tonnes of refrigeration (TR), where 1 TR = 3.517 kW of cooling.
- Domestic fridges serve small enclosures with intermittent door openings.
Concept / Approach:Compact, insulated household units require modest cooling capacities, far below split ACs or chillers. Typical single-door and double-door home refrigerators fall in the fraction-of-a-ton range.
Step-by-Step Solution:
Convert mental benchmark: 0.1 TR ≈ 0.35 kW; 0.3 TR ≈ 1.06 kW.These levels align with compressor sizes used in domestic refrigerators.Thus, 0.1–0.3 TR is the correct range.Verification / Alternative check:Compare to room air conditioners (commonly 1–2 TR): far larger than a fridge. Industrial or central plant capacities (3–7 TR and above) are orders of magnitude higher.
Why Other Options Are Wrong:
1–3 TR and above represent space conditioning or small commercial refrigeration, not typical household units.0.5–1.0 TR still overestimates most domestic fridges.
Common Pitfalls:Confusing electrical power (kW input) with cooling capacity (kW or TR). Always compare like quantities.
Final Answer:
0.1 to 0.3 TR